1. Field of the Invention
The invention relates to a semiconductor package technique and more particularly to a chip package structure and a manufacturing method thereof.
2. Description of Related Art
Semiconductor package technique includes various package types. With the trend of miniaturization and thinning of chip package structures, the quad flat no-lead (QFN) package of the flat package type is developed. In the manufacturing process of the QFN package, a chip is first disposed on a die pad of a leadframe. A wire bonding process is then performed to electrically connect the chip to a plurality of leads of the leadframe through a plurality of bonding wires. Afterwards, the QFN package is completed by encapsulating the chip, the bonding wires, and the leadframe with an encapsulant.
Generally, each of the leads includes a suspending portion and the encapsulant fills the space underneath the suspending portions to establish a mold lock between the encapsulant and the leads, thereby preventing the encapsulant from peeling off from the leadframe. However, in the wire bonding process aforementioned, the suspending portions of the leads may sway or deform due to the downward force. As a consequence, the bonding wires cannot be firmly bonded to the leads effectively and are prone to peeling off from the leads, thereby leading to poor electrical connection or electrical failure. Moreover, in the encapsulating process, the suspending portions of the leads may shift easily due to the molding flow, which leads to bridging of the leads, and therefore an electrical short.